Todo List: x264/libx264 split

In order to support 10bit depth in x264, the package has been split into three standalone packages: x264 (containing CLI tools and development headers) and libx264/libx264-10bit.

Please confirm whether your packages make use of command line utilities and if not, replace the dependency on x264 with libx264. Note that x264 in [staging] doesn't pull libx264 anymore. It may be also needed to put x264 explicitly in makedepends array.